The saying “a picture is worth a thousand words” is often used to explain how a complex situation, idea, or thought can be conveyed with a single still picture. There are many examples of when this is true, such as in the media when a poignant photograph expresses some joyful, or unfortunately more often some heartbreaking situation much better than any article could.

A perfect example of a heartbreaking picture expressing a 1000+ words

And there are many examples when pictures can convey an idea or information effectively and easily within healthcare, such as the use of an info-graphic to help disseminate scientific literature and research just like Yann Le Meur @YLMSportScience and Chris Beardsley @SandCResearchdo so very well. Then there are other images that can get across a message or an idea simpler, quicker, easier than a blog or an article could such as my recent ‘physio…

5. Muscle weakness or #Imbalance – Weak #glute muscles and deep leg muscles INCREASE the Q angle. A SHORTENED INCIDENTS calf head and #POPLITEUS also turn the shin bone inwards INCREASING the Q angle.
Some of these factors can be resolved with treatment and #rehabilitation.

– #Patella Alta – above left diagram. Generally kneecaps sit in the groove and the bottom of the kneecap is about level with the joint line. However, people born with an unusually high knee cap or those left with one after surgery are susceptible to much faster degeneration of the back of the kneecap as it doesn’t sit in the groove well.

If the bottom angle of the #kneecap is line with or below the joint line (imaginary line where the knee bends) this is considered to be ‘normal’ or less likely for #cartilage damage to occur as quickly as when it is high.

– #Trochlear Dysplasia – see above bottom right. This is when instead of having a stable groove to sit in. The kneecap sits in a shallow or flat groove. This allows excessive movement particularly right and left and decreases stability of the patella. It can lead to increased incidences of #dislocation and faster degeneration. When moving the kneecap side to side in a stable trochlear, the kneecap should rise a little when pushing to the outside of the leg.

Test for a shallow groove is done using the inverted J sign

– Patella Tilt – see above top right. If the patella is tilted one side more than the other, there is more chance of wearing on the side closer to the thigh bone. One tests this by springing the kneecap on the right and left sides.

Patella Testing:

1. Inverted J Sign – sit on high surface knees dangling of the side. Extend and flex knees, watch for patella moving excessively up and out as the knee extends or see link below.

Above is a picture of the patella/kneecap. #Patellofemoral pain is a range of pains or disorders that can be anything from mild discomfort to severe pain. The pain is thought to originate from contact between the back of the knee cap and the thigh bone.

The pain source of the cartilage is controversial. Many studies indicate it is not the #cartilage on the back of the kneecap but the soft tissues around the knee or the bone underneath the cartilage (subchondral bone) that causes the pain.

1. Pain around the kneecap, usually hard to pinpoint and can feel deep or behind it.
2. Clicking in the knee while flexing and extending it.
3. A feeling of giving way.
4. Catching or locking.
5. Worse after sitting for a long time, known as a positive cinema sign.
6. Worsens after repeated squatting. Especially very low ones past 90 degrees.
7. Worse after increased loading in the knee after the following activities where the knee is flexed and the quads have to contract forcefully): (Loading through the knee is mentioned in number of times of your bodyweight (BW) going through the knee) – Upstairs –> 3x BW
– Downstairs –> 5x BW
– Jumping –> 5x BW
– #Squatting –> 5x BW
– Running
8. Swelling

So that you have an idea of the function of the patella aka kneecap, I have drawn 3 images above that I hope will help.

As the knee bends from a totally straight position to a totally flexed position there are different structures that come into contact with the kneecap, which help in diagnosis of knee pain. So…
In full extension (straight leg) there is minimal compression on the back of the kneecap. However HOFA’S FAT PAD can be caught, so banana shaped pain in full extension under the knee cap may be due to the fat pad (also pinches in full flexion). See diagram.

As the knee begins to bend, the kneecap gradually gets more and more compressed from behind by the thigh bone.
At 20 – 30 degrees –> it begins to come into contact with the groove it sits in between the condyles shown in the bottom left picture and it keeps sliding down as the knee flexes more.

At 90 degrees flexion – most of the back of the knee cap has come into contact with the thigh bone behind.
Between 0 and 90 degrees the compression force on the kneecap increases. This combined with the large contact area helps to DECREASE the load on the kneecap.

But 90 degrees flexion – a SMALLER contact area on the back of the kneecap and INCREASED quadriceps compression on the kneecap INCREASES the load on the knee cap.

This is why squatting, >90 degrees may not be the best idea given that at least 6 times your bodyweight if not more
is going through the area.

The top image shows how the kneecap is influenced by muscles and other soft tissue.

The forces on the inside of the kneecap that help control its movement are:

1. VMO – The inner most quadricep muscle

2. Retinaculum

The forces on the outside of the kneecap:

1. ITB – Iliotibial band, popular area thats a common cause of pain in runners and an area people love foam rolling.

2. VML – the outside quadriceps muscle.

3. Retinaculum

Any weakness or wasting in these muscles can lead to poor movement of the patella and pain. Muscle tone and strength of the quadriceps is therefore important.

The Straight Leg raise is great way to strengthen without impacting the kneecap.